Welding-related brain and functional changes in welders with chronic and low-level exposure
| Autor: | Michael R. Flynn, Richard B. Mailman, Eun Young Lee, Mechelle M. Lewis, Xuemei Huang |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Adult
Male 0301 basic medicine medicine.medical_specialty Iron Motor Disorders Welding Toxicology Asymptomatic Article Developmental psychology law.invention 03 medical and health sciences 0302 clinical medicine law Occupational Exposure Internal medicine Basal ganglia Fractional anisotropy medicine Humans Manganese Manganese Poisoning General Neuroscience Neurotoxicity Brain Low level exposure Middle Aged medicine.disease 030104 developmental biology Endocrinology Globus pallidus medicine.symptom Psychology 030217 neurology & neurosurgery Diffusion MRI |
| Zdroj: | NeuroToxicology. 64:50-59 |
| ISSN: | 0161-813X |
| DOI: | 10.1016/j.neuro.2017.06.011 |
| Popis: | Although an essential nutrient, manganese (Mn) can be toxic at high doses. There is, however, uncertainty regarding the effects of chronic low-level Mn-exposure. This review provides an overview of Mn-related brain and functional changes based on studies of a cohort of asymptomatic welders who had lower Mn-exposure than in most previous work. In welders with low-level Mn-exposure, we found: 1) Mn may accumulate in the brain in a non-linear fashion: MRI R1 (1/T1) signals significantly increased only after a critical level of exposure was reached (e.g., ≥300 welding hours in the past 90 days prior to MRI). Moreover, R1 may be a more sensitive marker to capture short-term dynamic changes in Mn accumulation than the pallidal index [T1-weighted intensity ratio of the globus pallidus vs. frontal white matter], a traditional marker for Mn accumulation; 2) Chronic Mn-exposure may lead to microstructural changes as indicated by lower diffusion tensor fractional anisotropy values in the basal ganglia (BG), especially when welding years exceeded more than 30 years; 3) Mn-related subtle motor dysfunctions can be captured sensitively by synergy metrics (indices for movement stability), whereas traditional fine motor tasks failed to detect any significant differences; and 4) Iron (Fe) also may play a role in welding-related neurotoxicity, especially at low-level Mn-exposure, evidenced by higher R2* values (an estimate for brain Fe accumulation) in the BG. Moreover, higher R2* values were associated with lower phonemic fluency performance. These findings may guide future studies and the development of occupation- and public health-related polices involving Mn-exposure. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect